Apparatus for testing the brakes on airplane ground wheels



Oct. 15, 1946. a. E. BOCK 2,409,457

APPARATUS FQH TESTING THE BRAKES ON AIRPLANE GRQUND WHEELS Fil ed Jan. 2s, 1943 v 4 Shees-She et 1 Oct. 15, :1946. G. E. BOCK 2,409,457

APPARATUS FOR TESTING THE BRAKES ON AIRPLANE-GROUND WHEELS Filed Jan. 25, 1943 4 Sheets-Sheet 2 Oct. 15, 1 946. 7 G. E. Boc I 2,409,467

APPARATUS FOR TESTING T.HE BRAKES ON AIRPLANE- GRGUND WHEELS Filed Jan. '25, 1945 4 Sheets-Sheet 3 I' 4; 5 e lye 0.6 y 91 Oct. 15, 1946. I G. E; BOCK 2,409,467

AI PA RATUSFOR TESTING THE BRAKES ON AIRPLANE GROUND WHEELS .Fned Jan. 23, 1943 4 shets-sne z 4 lU|F Patented Oct. 15, 1946 APPARATUS FOR TESTING THE BRAKES N AIRPLANE GROUND WHEELS George E. Book, Chicago, 111., assignorto Whiting Corporation, Harvey, ILL, a corporation of Illi} nois Application January 23, 1943, Serial No. 473,334

The present invention relates generally to apparatus for testing brakes on the main ground wheels of an airplane. More particularly the invention relates to that type of airplane brake testing apparatus which comprises a pair ofopposed, complemental units each of which is located in a pit and embodies a pair of side by side, horizontally positioned wheel supporting rollers, one of which is an idler and the other of which is connected for drive by a constant speed electric motor. One object of the invention is to provide an airplane brake testing apparatus of this type which is an improvement upon, and is mor effi-g cient than, previously designed brake testing apparatus and is characterized by the fact that it is so designed and constructed that the airplane, the brakes of Which ar to be tested by the apparatus, is not subjected to any appreciable shock when the Wheels thereof ar ers of the units. i

Another object of the invention is to provide an apparatus of the type and character under consideration in which the pits for the two units have covers which are adapted to support the wheels of the airplane when the airplane is rolled or propelled into a brake testing position and are further adapted when the airplane is elevated to a slight extent by way of hydraulic jacks or the like, to be removed or shifted into an open position in order to expose the rollers and permit, th airplane to be lowered into a position wherein the main ground wheels are supported on the rollers.

A further object of the invention is to provide an airplane brake testing apparatus of the last mentioned type in which the pit covers are articulate and have associated therewith power means for shifting them back and forthbetween their open and closed positions. 1

A still further object of the invention is to provide an airplane brake testing. apparatus which is generally of new and improved construction and is characterized by the fact that the two complemental units are both rugged and durable and effectively and efficiently perform their intended function.

Other objects of the invention and the various advantages and characteristics of the present airplane brake testing apparatus will be apparent from a consideration of the following detailed description. The invention consists in the several nove features which are hereinafter set forth and are placed on the roll-- can. (01. 73--126) more particularly defined by claims at the connote corresponding parts throughout the several views: I i

Figure l is a plan view showing an airplane disposed in a brake testing position with respect to a testing apparatus embodying the invention;

Figure 2 is a-front view of the airplane showing the wheels thereof while supported on the articulate pit covers that overlie the wheel supporting rollers of the units;

Figure 3 is a front view of the airplane showing it supported by way of jacks and the articulate pit covers shifted into their open position preparatory to lowering the airplane so as to bring the wheels onto the rollers;

Figure 4 is a plan view of the left hand the cover for the pit thereof being omitted;

Figure 5 is a vertical, longitudinal section taken on the line 5-5 of Figure 4 and illustrating in detail the construction arid design of the power mechanism for shifting the articulate cover for the pit of the left handunit back and forth between its open and closed positions;

Figure 6 is a vertical, transverse section taken on the line 6-6 of Figure 5 and showing the design and arrangement'of the wheel supporting rollers of the left hand unit; and I Figure '7 is a plan view of the articulate, cover for the pit forthe left hand unit. The apparatus which is shown in the drawings constitutes thepreferred form or embodiment of the invention. It is illustrated in connection with an airplane A having aspart of the landing gear thereof a pair of brake equipped opposed main ground wheels at and serves as a medium for testing. the brakes for the wheels a. As its main or component parts the apparatus comprises a pair of complemental units 8 and 9. These units are positioned one opposite the other and are adapted to support the airplane wheels a in connection'with .a braketesting operation. The unit 8 is disposed in an L-shaped pit In and is designed to support the left hand main ground wheel a of the airplane A; The unit 9 is mounted or disposed in an'L-shaned pit H and is designed to support the other'main ground wheel of the airplane, i. e., the right hand wheel a. l

The pit l l for the left hand unit, i. e., the unit 8, is of uniform depth and comprises an inner leg Hi and an outer leg la The inner leglis arranged or located so that it extends spanwise unit,

of the wing of the airplane A when the airplane is in its brake testin position. The outer leg 10* of the pit Ill is in communication with, and leads forwards from, the inner leg Ill and extends at right angles to the latter. The pit ID is normally closed by a composite cover 12 which, when in its closed position, is flush with the surface or other foundation in which the pit i9 is formed. As shown in Figure 7 of the drawings, the cover l2 comprises a plurality of sections l2**, l2 l2, I2 l2 and l2 and these are arranged in series form and extend transversely of the pit 10. The cover sections l2 62 and l2 serve .to cover or close the outer leg [li of the pit I3 and the cover sections l2 l2 and l2 serve as a closure medium for the inner leg w of the pit. The cover section 12 extends across the outer end of the pit leg 10 and is supported at the ends thereof on a pair of angle bar type rails l3 which extend along the upper portions of the front and rear walls of the pit leg HP and have horizontally extending flanges. The latter are disposed in shallow grooves along theupper portions of the-front and rear walls of the outerleg NW of the pit it. The cover section l2 normally remains in place but, however, may be removed in the event access is desired to the portion of the pit below it. The cover section iZPextends normally across the central portion of the pit leg It and is supported at the ends thereof by the rails E3. The next section of the cover, i. e., the section l2, extends normally across the inner portion of the leg 10 of the pit and, like the sections I2 and [2 is supported by the ends of the rails- I3. The two cover sections I 2 and I 2 are connected together by pivotal connections M and are adapted, as hereinafter described, to be slid or shifted inwards and upwards into an open position as shown by full lines in Figure 3 and by dotted lines in Figure 5. The pivotal connections M are disposed atthe-adiacent corners of the cover sections [2 and l2 and consist of overlapping lugs and'pi'vot pins between the lugs. The cover section' I 2 is provided at the outer corners thereof with small sized wheels l5 and these are arranged to travel on the rails l3 in connection with shift of the articulate cover sections I2 and [2 back and forth between their open and closed positions. As will be pointed out hereafter, the cover sections l2 and I2 are positioned in their closed position when the airplane is brought or propelled into its brake testing position. When in their closed position such cover sections are flush with the ground or foundation in which the pit'l'fi is formed. and underlie and serve to supportthe left hand main ground wheel a of the airplane A. After the airplane is brought into its brake testing position it is raised a small distance by way of a pair of hydraulic jacks J (see Figures 2 and 3). Thereafter the articulate cover sections 12 and l2 are shifted into their open position'and the airplane is lowered by proper manipulation of the jacks. The jacks are generallyplaced under the outboard sections of the wing of the airplane and are preferably of the tripod type. The cover sections l2 and 22 are formed of plate steel and areso designedor constructed'thati'they are capable of supporting the portion of the airplane which is disposed thereover when the airplane is in its brake testing position. The cover sections 12 i2 and l2 are normally fixed or stationary and extend across the outer end, central portion, and inner end of the inner pit leg Ill respectively. They are, however, removable in order to-provide access to 4 the pit leg Ill and have handles at the ends thereof whereby they may be manipulated in connection with removal or installation thereof. The cover sections I2 and l2 are supported at their ends by a pair of horizontally extending angle bar type rails I5 which are disposed along the upper portions of the front and rear walls of the inner leg Id of the pit to. The rear end of the cover section 12 is supported on the rail i6 'atthe upper portion of the rear wall of the pit leg It and the front end of the cover section l2 terminates short of the other rail and is supported on a bracket I! in the pit it. The space between the front end of the cover section l2* and the adjacent endof the rail l5 that extends along the upper portion of the front wall of the pit leg It] is normally closed or covered by a plate I 3.

The left hand unit 8 in the pit it is of unitary design and comprises a supporting frame 59 and a pair of side by side, horizontally extending rollers Eli-and 2!. The frame is L-shaped in conformity with the contour of the pit, and rests on the pit bottom. It serves as a supporting medium for the rollers 29 and 2! and embodies apair of laterally spaced, transversely extending channel beams 22 and 23 in the outer leg Ni of the pit it, a transversely extending angle bar 24 in the inner end of the inner pit leg Ill and a plurality of longitudinally extending beams 25, 26, 21, 28 and 29. The channel beams'22 and 23 extend from the rear wall of the pit leg W to the front Wall and are maintained in spaced relation by the longitudinally extending beams 25, 25 and 21. The beam 27 is located adjacent the rear Wall of the pit leg l and has the inner end thereof extended to connect to the angle bar 26. The beams 28 and 29 are located in the inner leg M of the pit and extend between, and serve to space apart, the angle bar 24 and the channel beam 23. The various elements or parts of the frame are preferably welded together in order that the frame as a whole is rigid. The roller 29 is located in the front portion of the pit leg 18* and is disposed in parallel relation with the pit leg ic It is an idler roller and embodies a supporting shaft 38, the ends of'which are mounted in bearings 36 on the front ends of the channel beams 22 and 23. Preferably the periphery of the roller '28 is ribbed or fluted for wheel gripping purposes. The rollerZl is located in the rear portion of the outer leg E'O of the pit If) and is disposed in parallel relation with the idler roller 29. It embodies a ribbed or fluted periphery like that of the idler roller and has a longitudinal supporting'shaft the ends of which are journallecl in bearings 0n the rear ends of the channel beams 22 and 23 of the'frarne iii. In connection with a brake testing operation the left hand Wheel of the-airplane to be tested is lowered ontothe two rollers 29 and 2|, as shown by dotted lines in Figure 6, and when in place is supported by the rollers. The roller 2| is driven by Way of a constant speed electric motor 34. The latter is mounted on a platform 35 over the inner ends of the beams 27 and 29 and, is disposed in coaxial relation with the supporting shaft 32 for the roller H. The end of the armature shaft of the electric motor that projects in the direction of the roller 2! is con-- nected to the drive shaft of a speed reducer 35. The driven shaft of the speed reducer is connected to the inner end of the supporting shaft 32 of the roller ill by way of a coupling "F speed reducer 36 is mounted on the on of the platform 35 and is protected by hou 38. During use of the left hand unit'B the electric rollers 20 and 2| and the motor 34 for driving the roller 2! is supplied with current the current input, as recorded on the watt meter, shows the drag of the brake for the wheel.

In addition to the parts heretofore enumerated the left hand unit 6 oft-he apparatus comprises power means for shifting the articulate cover sections lZ and |2 back and forth between their open and closed positions. I This means comprises an electric motor 39, a speed reducer 4G, a pinion 4|, a sector shaped gear 42, and a pair of arms 43. The motor 39 is of the reversible type and is mounted between the rollers Zll and 2! on a bracket 44. The latter is welded orotherwise fixedly secured to the central portion of the outer face of the channel beam 23. The motor 39 is disposed in parallel relation with the two rollers and has the inner end of the armature shaft thereof connected to the drive shaft of the speed reducer 40. As shown in Figures a. and 5, this speed reducer is mounted on a bed plate which extends across the outer ends of the longitudinally extending beams 28 and 29 of the frame Hi. The driven shaft of the speed reducer 4% extends at right angles to the drive shaft and is normal to, and overlies, the outer end of the frame beam 28. The pinion 4| meshes with, and serves to drive, the sector shaped gear 42 and is fixed to the front or forward end of the driven shaft of the speed reducer 4d. The gear 4?. is disposed adjacent the front wall of the inner leg Ili of the pit and 1s mounted on a stub axle t?! so that it is capable of swinging in a vertical plane. It is normally disposed within the pit, as shown in Figure 5, and carries the arms 43 at the upper portion thereof. The stub axle 42 extends through a bearing in the apex or central portion of the sector shaped gear 42 and is carried by a bracket 45 which 15 secured to, and projects laterally from, the housing 38 for the speed reducer 38. The arms 43 extend radially from the stub axle 42 and are fixed to, and disposed in straddled relation with, the upper portion of the gear 42. They are positioned horn zontally when the articulate cover sections li and I2 are in their closed position and have the distal ends thereof connected by a pivot pin 46 to a lug 4! on the central inner portion of tle cover section l2. When the electric motor as is driven in one direction so as to cause the gear 42 to rotate or rock in a counterclockwise direction as viewed in Figure 5, the arms 43 are swung upwards and cause the articulate cover sections l2 and i2 to slide inwards and upwards as shown by dotted lines in Figure 5. Reverse drive of the electric motor 39 causes the gear 42 to rotate or rock in a clockwise direction as viewed in Figure 5, and results in the arms 43 sliding the articulate cover sections l2 and lif downwards and outwards into their closed position wherein they overlie the rollers 20 and ti. Limit switches (not shown) are preferably provided in order to control the motor so that it stops automatically when the articulate cover sections reach their full open. position and. their full closed position. The cover sections it! and it are so dimensioned or proportioned that they fully overlie the r 11ers 2d and 2| when they are in their closed position. They are provided on the bottom portions thereof with shoes 48 which rest on the top portions of the two rollers when the two sections are in their closed position. The shoes 48 extend lengthwise of the rollers and are in sliding engagement therewith. By employing shoes the two articulate cover, sections l'l and 12 are supported, not only by the rails l3, but also by the rollers when they are in their closed position. During shift of the cover sections I2 and [2 out of and into their closed position the small sized wheels IE on the outer corners of the cover section l2? ride or travel on the rails l3' as heretofore described. When the cover sections I2 and 12 are in their closed position the upper surfaces thereof are flush with theupper surfaces of the other sections of the cover [2 and permit the left hand ground wheel a of the airplane A to be rolled onto them; The plate l8 serves to complete the cover [2 and is mounted on the upper inner portion of the arms 43. When the arms are horizontally disposed while the articulate cover sections are in their closed positions, the plate I8 is flush with all the sections of the cover.

The L-shaped pit H for the right hand unit 9, i. e., the unit for supporting the right hand main ground wheel a of the airplane A in connection with a brake testing operation, is positioned opposite to the pit it (see Figure 1), but is reversely arranged. It is spaced from the pit In so that the outer leg thereof is beneath the right hand wheel a of the airplane when the airplane is in its brake testing position with respect to the apparatus. A composite cover 49, exactly like the cover i2, serves as a medium for closing or covering the pit II. It includes certain normally stationary sections and two articulate sections corresponding to the sections I2 and ll of the cover :2.

the right hand main ground wheel a of the airplane A is the same as the unit 8 except that it is reverseh positioned. It functions or operates in the same manner as the unit 8 and comprises a frame 59 in the pit l l, a pair of wheel supporting rollersiii and 52, an electric motor 53 for driving the roller 52 and power means for shifting the articulate sections of the cover back and forth between their open and closed positions. The power means is identical to the power means of theunit 8 for actuating the articulate cover sections I? and i2 of the cover l2 and comprises an electric motor (not shown), a speed reducer (alsonot. shown), a pinion 54, a sector shaped gear and a'pair of arms 56. The electric motor of the power means for actuating the articulate cover sectionsof the cover 49 for the pit II is of the reversible variety, the same as the 55 electric motor 39. p p p In using the improved brake testing apparatusthe airplaneA to be tested ispropelled so as to bring the main ground supporting wheels (1 thereof onto thearticulate sections of the pit ocovers, as shown in Figure 2. Thereafterthe hydraulic jacks J are placed under the outboard wing sections of the airplane and are manipulated so as to elevate the airplane sufficiently to bring the main ground wheels out of engagement with. the aforementioned articulate cover sections. After the airplane is elevated by Way of the jacks to the desired or proper extent the articulate sections of the pit covers are shifted inwards and upwards into their open position by actuation of the aforementioned power means therefor. When the articulate sections of the two pit covers are in their open position, as shown in Figure 3, the main ground wheels not the airplane A are disposed over the brake testingrollers in the outer legs of the two pits. After open- The unit 9 for supporting and brake testing ing of the pit covers by inward and upward sliding of the articulate cover sections the jacks J are actuated or manipulated so as to lower the airplane into a position wherein the ground wheels a rest on the rollers. Thereafter the electric motors 34 and 53 are started so as to effect drive of the driven rollers 2| and 52. During drive of the driven rollers the brakes are set or adjusted so as to equalize their drag on the ground wheels a. At the conclusion of the brake testing operation the jacks are actuated so as to elevate the airplane A and the articulate sections of the two pit sections are then shifted outwards and downwards into their closed position wherein they overlie the rollers and are so arranged as to support the ground wheels upon lowering of the airplane.

The herein described brake testing apparatus effectivel and efficiently fulfills its intended function and is characterized by the fact that when it is properly manipulated the airplane to be tested is not subjected to any appreciable shock when the main ground wheels thereof are placed on. the testing rollers of the units. By eliminating shock to the airplane being tested, the possibility of injuring the radio and other delicate instruments for the airplane is avoided. The apparatus is further characterized by the fact that the two complemental units thereof are both. rugged and durable and the articulate sections of the pit covers are so designed and constructed that they are capable of supporting the airplane when the ground wheels are rol ed thereon preparatory to a brake testing operation.

The invention is not to be understood as restricted to the details set forth since these may be modified within the scope of the appended claims withoutdeparting from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. The combination with a pit having therein a pair of side by side rollers for use in testing the brake on a vehicle wheel, of a platform type element at the top of the pit mounted so that it is shiftable back and forth lengthwise of the rollers between an operative position wherein it overlies, and is supported directly on, the rollers and an inoperative position wherein it is free or clear of said rollers, and adapted and designed, when in its operative position, to have the vehicle wheel propelled thereon and to support said wheel, and further adapted, upon elevation of the wheel, to

be shifted into its inoperative position so as to i 1 permit the wheel to be lowered into operative relation with the brake testing rollers, and means including an electric motor and gearing in the pit for shifting the element back and forth between its operative and inoperative positions.

2, The combination with a pit having means therein for testing a vehicle wheel brake, of a cover for the pit embodying a part mounted so that it is shiftable'back and forth between an operative position wherein it overlies the means and an inoperative position wherein it is disposed upwards and to one side of said means, adapted and designed when in its operative position to havethevehicle wheel propelled thereon and to support said wheel, and further adapted upon elevation of the wheel to be shifted into its inoperative position so as to permit the wheel to be lowered into engagement with the brake testing means, and power actuated means for moving the between an operative position wherein they are supported directly on the rollers and an inoperative position wherein they are disposed upwards and to one side of said rollers, adapted and designed, when in their operative position, to have .the vehicle wheel propelled thereon and to support said wheel, and further adapted, upon elevation of the wheel, to be shifted to their inoperative position so as topermit the wheel to be lowered into operative relation with the brake testing rollers, and power actuated means in the pit for moving said sections back and forth between their operative and inoperative positions.

4. The combination with a pit having therein a pair of side by side rollers for use in testing a vehicle wheel brake, of a composite cover for the pit comprising normally stationary but removable sections above and outwards of the rollers and a plurality of articulate sections-mountedso that they are shiftable back and forth between an operative position wherein they overlie the roll ers and an inoperative position wherein they are disposed upwards and to one side of the rollers, adapted and designed, when in their operative position, to have the vehicle Wheel propelled thereon and to support said wheel, and further adapted, upon elevation of the wheel, to be shifted to their inoperative position so as to permit the wheel to be lowered into operative relation with the brake testing rollers, and power actuated means in the pit for shifting the articulate cover sections back and forth between their operative and inoperative positions, said means being disposed for the most part beneath the normally stationary sections when the latter are in place and being accessible upon the removal of the last mentioned sections.

5. The combination with a pit having therein a pair of side by side rollers'for use in testing the brake of a vehicle wheel, of a composite cover for the pit comprising normally stationary but removable sections to one side of the rollers, a plurality of articulate sections mounted so that they are shiftable back and forth lengthwise of the rollers between an operative position wherein they overlie and are supported directly on the rollers and an inoperative position wherein they extend upwards and to one side of the rollers and expose the latter, adapted and designed, when in their operative position to have the vehicle wheel propelled thereon and to support said wheel, and further, adapted, upon elevation of the wheel, to be shifted to their inoperative position so as to permit the wheel to be lowered into operative relation with the brake testing rollers, and power actuated means in the pit for shifting the articulate cover sections back and forth between their operative and inoperative positions, including a swing type arm having one end thereof mounted for pivotal movement on a fixed pivot and its other end pivotally connected to one of the or ticulate sections.

GEORGE E. BOCK. 

